drivers/scsi/scsi_netlink.c

   1 /*
   2  *  scsi_netlink.c  - SCSI Transport Netlink Interface
   3  *
   4  *  Copyright (C) 2006   James Smart, Emulex Corporation
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21 #include <linux/time.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/security.h>
  24 #include <linux/delay.h>
  25 #include <linux/slab.h>
  26 #include <linux/export.h>
  27 #include <net/sock.h>
  28 #include <net/netlink.h>
  29
  30 #include <scsi/scsi_netlink.h>
  31 #include "scsi_priv.h"
  32
  33 struct sock *scsi_nl_sock = NULL;
  34 EXPORT_SYMBOL_GPL(scsi_nl_sock);
  35
  36 /**
  37  * scsi_nl_rcv_msg - Receive message handler.
  38  * @skb:                socket receive buffer
  39  *
  40  * Description: Extracts message from a receive buffer.
  41  *    Validates message header and calls appropriate transport message handler
  42  *
  43  *
  44  **/
  45 static void
  46 scsi_nl_rcv_msg(struct sk_buff *skb)
  47 {
  48         struct nlmsghdr *nlh;
  49         struct scsi_nl_hdr *hdr;
  50         u32 rlen;
  51         int err, tport;
  52
  53         while (skb->len >= NLMSG_SPACE(0)) {
  54                 err = 0;
  55
  56                 nlh = nlmsg_hdr(skb);
  57                 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
  58                     (skb->len < nlh->nlmsg_len)) {
  59                         printk(KERN_WARNING "%s: discarding partial skb\n",
  60                                  __func__);
  61                         return;
  62                 }
  63
  64                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
  65                 if (rlen > skb->len)
  66                         rlen = skb->len;
  67
  68                 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
  69                         err = -EBADMSG;
  70                         goto next_msg;
  71                 }
  72
  73                 hdr = NLMSG_DATA(nlh);
  74                 if ((hdr->version != SCSI_NL_VERSION) ||
  75                     (hdr->magic != SCSI_NL_MAGIC)) {
  76                         err = -EPROTOTYPE;
  77                         goto next_msg;
  78                 }
  79
  80                 if (!capable(CAP_SYS_ADMIN)) {
  81                         err = -EPERM;
  82                         goto next_msg;
  83                 }
  84
  85                 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
  86                         printk(KERN_WARNING "%s: discarding partial message\n",
  87                                  __func__);
  88                         goto next_msg;
  89                 }
  90
  91                 /*
  92                  * Deliver message to the appropriate transport
  93                  */
  94                 tport = hdr->transport;
  95                 if (tport == SCSI_NL_TRANSPORT) {
  96                         switch (hdr->msgtype) {
  97                         case SCSI_NL_SHOST_VENDOR:
  98                                 /* Locate the driver that corresponds to the message */
  99                                 err = -ESRCH;
 100                                 break;
 101                         default:
 102                                 err = -EBADR;
 103                                 break;
 104                         }
 105                         if (err)
 106                                 printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
 107                                        __func__, hdr->msgtype, err);
 108                 }
 109                 else
 110                         err = -ENOENT;
 111
 112 next_msg:
 113                 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
 114                         netlink_ack(skb, nlh, err);
 115
 116                 skb_pull(skb, rlen);
 117         }
 118 }
 119
 120 /**
 121  * scsi_netlink_init - Called by SCSI subsystem to initialize
 122  *      the SCSI transport netlink interface
 123  *
 124  **/
 125 void
 126 scsi_netlink_init(void)
 127 {
 128         struct netlink_kernel_cfg cfg = {
 129                 .input  = scsi_nl_rcv_msg,
 130                 .groups = SCSI_NL_GRP_CNT,
 131         };
 132
 133         scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
 134                                              &cfg);
 135         if (!scsi_nl_sock) {
 136                 printk(KERN_ERR "%s: register of receive handler failed\n",
 137                                 __func__);
 138                 return;
 139         }
 140
 141         return;
 142 }
 143
 144
 145 /**
 146  * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
 147  *
 148  **/
 149 void
 150 scsi_netlink_exit(void)
 151 {
 152         if (scsi_nl_sock) {
 153                 netlink_kernel_release(scsi_nl_sock);
 154         }
 155
 156         return;
 157 }
 158